EP0524009B1 - Video signal processing apparatus for reducing aliasing interference - Google Patents
Video signal processing apparatus for reducing aliasing interference Download PDFInfo
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- EP0524009B1 EP0524009B1 EP92306558A EP92306558A EP0524009B1 EP 0524009 B1 EP0524009 B1 EP 0524009B1 EP 92306558 A EP92306558 A EP 92306558A EP 92306558 A EP92306558 A EP 92306558A EP 0524009 B1 EP0524009 B1 EP 0524009B1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/015—High-definition television systems
- H04N7/0152—High-definition television systems using spatial or temporal subsampling
Definitions
- This invention relates to a video signal processing apparatus for restoring a high definition television signal which has been subjected to bandwidth compression using a sub-Nyquist sub-sampling method and transmitted.
- a high definition television (HDTV) signal has a frequency bandwidth exceeding 20 MHz and is required to be subjected to bandwidth compression by any means when to be transmitted using a satellite or the like.
- a sub-Nyquist sub-sampling method As an effective method for broadly compressing a frequency bandwidth of HDTV signal, there has been known a sub-Nyquist sub-sampling method.
- MUSE multiple sub-Nyquist sampling encoding
- HD-MAC high definition-multiple analogue component
- an offset sub-sampling is carried out in an inter-field and inter-frame manner to transmit a quarter of the sample points of an original signal and as a result, the perfect picture is transmitted in a four-field mode; so that the bandwidth of the original signal is compressed quarterly.
- a sample point untransmitted is interpolated from the sample point transmitted, thus restoring the original signal.
- interpolation is made using all sample points of present field and past three fields.
- interpolation is made using only an intra-field sample point that is transmitted.
- the stationary area and moving area are different in interpolating method from each other.
- the motion of an image is detected and an image interpolated for the stationary area and an image interpolated for the moving area are mixed with each other in accordance with the motion of an image thus detected, thus restoring the image.
- an inputted MUSE signal is sent to an interpolating circuit to interpolate a non-sample point from an intra-field sample point in order to restore a bandwidth-compressed signal.
- the signal subjected to intra-field interpolating process which is equivalent to the moving image processing of an MUSE decoder, in the interpolating circuit has signal transmission characteristics as shown in a frequency characteristics chart of Fig. 12(a).
- a frequency characteristics chart of Fig. 12(a) As a result, for the stationary area, the high resolution component of a high definition television signal by offset sub-sampling of the MUSE system as shown in a frequency characteristics chart of Fig. 12(b) is reproduced as an aliasing interference, resulting in degradation in image quality.
- the signal thus processed through the interpolating circuit is sent to a frame memory to delay one frame period and then, the signal thus one-frame delayed and the signal thus processed interpolation are subjected to inter-frame averaging process through an adder, thus being obtainable such a signal that an aliasing interference due to inter-frame offset sub-sampling is eliminated.
- the inter-frame averaging process makes it possible to occur a double image, resulting in a degradation in image quality.
- an inputted MUSE signal is subjected to interpolation of non-sample point from an intra-field sample point in an interpolating circuit in order to restore a bandwidth-compressed signal.
- the signal thus interpolated is sent to field memories connected in series thereto, then, a median-value signal of three adjacent inter-field signals is taken out by a median-value signal selector, an output signal from the median-value signal selector and output signals from the field memories are averaged by an adder to obtain an average-value signal of the signals which are in an inter-field correlation with each other, thus being possible to obtain such a signal that the aliasing interference due to inter-field offset sub-sampling is eliminated.
- the averaging process of highly correlated inter-field signals between three adjacent signals is carried out adaptively, so that the aliasing interference due to inter-field offset sub-sampling of the MUSE system can be eliminated without giving any effect to the moving image.
- the aliasing interference due to inter-field offset sub-sampling can be eliminated and as a result, the flicker component of 30 Hz which is visibly appeared in a notched pattern in the vertical line area of an image so as to be adhesively formed thereto can be disappeared, however, the bandwidth-compressed MUSE signal contains the aliasing interference due to inter-frame offset sub-sampling still more, thus arising such a problem that a flicker component of 15 Hz is remained in the oblique component of the image.
- US-A-4 768 092 discloses the use of interpolation and averaging to convert a video signal to a higher resolution. Field and line differences are used to select various averaged signals.
- An object of this invention is to provide a video signal processing apparatus capable of eliminating both an aliasing interference due to inter-frame offset sub-sampling and aliasing interference due to inter-field offset sub-sampling.
- a video signal processing apparatus of this invention comprises an interpolating circuit for interpolating a non-sample point from intra-field sample points in order to restore a high definition television signal which has been bandwidth-compressed by offset sub-sampling, a first memory for delaying a signal thus interpolated for one field period, a second memory for delaying an output signal of the first memory for further one field period, a first adder for performing an adjacent inter-field averaging process from input and output signals of the first and second memories, a second adder for performing an inter-frame averaging process from an input signal of the first memory and an output signal of the second memory, a correlation discriminating circuit for detecting one field difference and one frame difference from input and output signals of the first and second memories and for outputting a switching signal in accordance with magnitudes of the differences thus detected, and a signal switching circuit for switching an output signal of the first adder and an output signal of the second adder in accordance with the output switching signal from the correlation discriminating
- this apparatus may further comprise a motion detection circuit for detecting a motion of an image from an input signal of the first memory and an output signal of the second memory, and a mixing circuit for mixing an output signal of the signal switching circuit and an input/output signal of the first memory in accordance with the motion of an image thus detected.
- a motion detection circuit for detecting a motion of an image from an input signal of the first memory and an output signal of the second memory
- a mixing circuit for mixing an output signal of the signal switching circuit and an input/output signal of the first memory in accordance with the motion of an image thus detected.
- Another video signal processing apparatus of this invention comprises a first memory for delaying the bandwidth-compressed high definition television signal for one field period, a second memory for delaying an output signal of the first memory for further one field period, first, second and third interpolating circuits for interpolating non-sample points from intra-field sample points in order to restore a sub-sampled signal in accordance with input and output signals of the first and second memories, a first adder for performing an adjacent inter-field averaging process from output signals of the first, second and third interpolating circuits, a second adder for performing an inter-frame averaging process from an output signal of the first interpolating circuit and an output signal of the third interpolating circuit, a correlation discriminating circuit for detecting one field difference and one frame difference from output signals of the first, second and third interpolating circuits and for outputting a switching signal in accordance with magnitudes of the differences thus detected, and a signal switching circuit for switching an output signal of the first adder and an output signal of the second adder in accordance with the
- a television signal subjected to intra-field interpolation is supplied to two memories. Then, an inter-field averaging process is performed between the present field and correlative adjacent field before or after for eliminating an aliasing interference due to inter-field offset sub-sampling, and an inter-frame averaging process is performed for eliminating an aliasing interference due to inter-frame offset sub-sampling. Larger one of these aliasing interferences is discriminated in accordance with the magnitudes of an inter-field difference and an inter-frame difference to be switched. Accordingly, not only the aliasing interference due to inter-field offset sub-sampling but also the aliasing interference due to inter-frame offset sub-sampling can be eliminated.
- the motion of an image Is detected, and the signal subjected to the inter-field averaging process between the present field and correlative adjacent field before or after, the signal subjected to the inter-frame averaging process, and the signal subjected to the intra-field interpolation are mixed with each other. Accordingly, even in case of a moving image, degradations including occurrence of double image can be prevented from being taken place.
- Fig. 2 is a block diagram showing in detail a circuit for detecting inter-field and inter-frame aliasing interferences to be taken place in the apparatus shown in Fig. 1.
- Fig. 4 is a block diagram of a video signal processing apparatus for reducing an aliasing interference according to a second embodiment of this invention.
- Fig. 5 is a block diagram of a video signal processing apparatus for reducing an aliasing interference according to a third embodiment of this invention.
- Fig. 6 is a block diagram of a video signal processing apparatus for reducing an aliasing interference according to a fourth embodiment of this invention.
- Fig. 7 is a block diagram of a median-value selection circuit in the apparatus shown in Figs. 2 and 4.
- Fig. 8 is a waveform diagram for explaining the operation of eliminating an inter-field aliasing interference in the apparatus shown in Figs. 2 and 4.
- Fig. 9 is a block diagram of a video signal processing apparatus for reducing an aliasing interference of the prior art.
- Fig. 10 is a block diagram of another video signal processing apparatus for reducing an aliasing interference of the prior art.
- Fig. 11 is a diagram for explaining the principle of a bandwidth compression method by MUSE system offset sub-sampling.
- Fig. 1 is a block diagram of a video signal processing apparatus for reducing aliasing interference according to a first embodiment of this invention, which comprises an input terminal 11 for receiving a high definition television signal which has been bandwidth-compressed by offset sub-sampling (hereinafter typically expressed as an MUSE signal), an interpolating circuit 12 for interpolating a non-sample point from an inter-field sample point in order to restore a bandwidth-compressed signal, field memories 13 and 14, adders 16 and 17 each for performing averaging process, a one field difference detection circuit 18 for detecting an aliasing interference due to inter-field offset sub-sampling, a one frame difference detection circuit 19 for detecting an aliasing interference due to inter-frame offset sub-sampling, a correlation discriminating circuit 20 for discriminating larger one of the inter-field and inter-frame aliasing interferences, and a signal switching circuit 21, and further comprising a motion detection circuit 22, a mixing circuit 23, and an output terminal 24 for taking out a high definition television signal having alia
- the MUSE signal inputted from the input terminal 11 is sent to the interpolating circuit 12 to interpolate a non-sample point from inter-field sample points in order to restore a bandwidth-compressed signal.
- the signal thus interpolated is sent to the field memories 13 and 14 connected in series.
- An output signal of the interpolating circuit 12 and an output signal of the field memory 13 is subjected to inter-field averaging process through the adder 16 to obtain a signal having an aliasing interference due to inter-field offset sub-sampling eliminated.
- the output signal of the interpolating circuit 12 and an output signal of the memory 14 are subjected to inter-frame averaging process through the adder 17 to obtain a signal having an aliasing interference due to inter-frame offset sub-sampling eliminated.
- input and output signals of the field memories 13 and 14 are respectively sent to the one field difference detection circuit 18 and one frame difference detection circuit 19 to detect an aliasing interference due to inter-field offset sub-sampling and an aliasing interference due to inter-frame offset sub-sampling, and sent to the correlation discriminating circuit 20 to discriminate larger one of the inter-field and inter-frame aliasing interferences.
- the signal switching circuit 21 controls the signal having an aliasing interference due to inter-field offset sub-sampling eliminated outputted from the adder 16 and the signal having an aliasing interference due to inter-frame offset sub-sampling eliminated outputted from the adder 17 so as to transmit the signal having eliminated the larger one of the inter-field and inter-frame aliasing interferences.
- the motion detection circuit 22 detects the motion of an image from the input signal of the field memory 13 and the output signal of the field memory 14.
- the signal outputted from the signal switching circuit 21, which is obtained by switching through the circuit 21 the signal subjected to inter-field averaging process before or after and the signal subjected to inter-frame averaging process, and the signal subjected to intra-field processing only outputted from the interpolating circuit 12 are mixed with each other through the mixing circuit 23 in accordance with the motion of an image thus detected. Accordingly, even in case of moving image, no degradation (occurrence of a double image) results, so that such a signal that aliasing interferences are substantially eliminated can be obtained from the output terminal 24.
- intra-field interpolation equivalent to the moving image process of an MUSE decoder is carried out in the interpolating circuit 12.
- the inter-field averaging process of the output signal of the interpolating circuit 12 and the output of the field memory 13 is carried out through the adder 16 to obtain such a signal that the aliasing interference due to inter-field offset sub-sampling is eliminated.
- the inter-frame averaging process of the output signal of the interpolating circuit 12 and the output signal of the field memory 14 is carried out through the adder 17 to obtain such a signal that the aliasing interference due to inter-frame offset sub-sampling is eliminated.
- the one field difference detection circuit 18 for detecting the absolute value of an inter-field difference from these signals of the three adjacent fields, the one frame difference detection circuit 19 for detecting the absolute value of an inter-frame difference therefrom and the correlation discriminating circuit 20 for comparing these differences to detect larger one of them in magnitude are disposed as shown in Fig. 2. As shown in Fig. 2,
- the signal subjected to processing for which is larger in aliasing interference is switched by the switching circuit 21 to be outputted.
- Fig. 4 is a block diagram of a video signal processing apparatus for reducing aliasing interference according to a second embodiment of this invention.
- a median-value signal selector 15 for extracting a median-value signal of three adjacent inter-field signals is additionally provided to the apparatus of the first embodiment so as to be disposed before the adder 16, and other components are the same as those in the first embodiment and indicated at the same referential numerals as above.
- the median-value signal selector 15 compares, as shown in Fig. 7, the magnitudes of respective two signals of three signals inputted with each other to detect a median-value signal on an amplitude selection basis therefrom.
- the selection means is switched in accordance with the result thus detected to output the median-value signal.
- the median-value signal selector 15 is not limited to that shown in Fig. 7, but any circuit can be used for this purpose if it can extract a median-value signal.
- Theoretical values of median-value selection in the median-value signal selector 15 are tabulatedly shown below.
- Fig. 8 is a waveform diagram for explaining the operation of eliminating an aliasing interference as an example.
- a median-value signal X (shown at ⁇ marks in Fig. 8) taken out through the median-value signal selector 15 becomes a signal before or after a signal Y of the present field (shown at o ⁇ marks in Fig. 8) as shown in Figs. 8(a) and (b). Accordingly, by being subjected to the inter-field averaging process on the median-value signal X and the signal Y of the present field through the adder 16, the aliasing component due to inter-field offset sub-sampling can be eliminated. On the other hand, in a moving area where an inputted television signal has a motion, as shown in Fig.
- the median-value signal X taken out through the median-value signal selector 15 becomes the signal Y of the present field.
- the signal Y of the present signal itself can be obtained, resulting in obtaining no degradation in image quality.
- the averaging process is performed adaptively on inter-field signals high in correlation between adjacent three fields, so that the aliasing interference due to inter-field offset sub-sampling of the MUSE system can be eliminated without giving any effect to the moving image itself. Further, even if the motion detection circuit 22 fails to discriminate the motion of an image, the effect of the inter-field averaging process on the moving image can be made small.
- MUSE signal inputted from the input terminal 31 is stored in the field memories 32 and 33 connected in series. Then, subjected to interpolation of a non-sample point from an intra-field sample point for a bandwidth-compressed signal of each of three adjacent fields. Next, an output signal of the interpolating circuit 34 and an output signal of the interpolating circuit 35 are subjected to inter-field averaging process through the adder 38 to obtain a signal having an aliasing interference due to inter-field offset sub-sampling eliminated.
- an output signal of the interpolating circuit 34 and an output signal of the interpolating circuit 36 are subjected to inter-frame averaging process through the adder 39 to obtain a signal having an aliasing interference due to inter-frame offset sub-sampling eliminated.
- interpolated signals of three adjacent fields of the interpolating circuits 34, 35 and 36 are sent to the one field difference detection circuit 40 and one frame difference detection circuit 41 to respectively detect the aliasing interference due to inter-field offset sub-sampling and the aliasing interference due to inter-frame offset sub-sampling. And then, the inter-field and inter-frame aliasing interferences are discriminated larger one of them through the correlation discriminating circuit.
- the switching circuit 43 controls the signal outputted from the adder 38 and having eliminated the aliasing interference due to inter-field sub-sampling by performing inter-field averaging process between the present field and correlative adjacent one before or after and the signal outputted from the adder 39 and having eliminated the aliasing interference due to inter-frame offset sub-sampling, so that the signal having eliminated larger one of these inter-field and inter-frame aliasing interferences can be passed therethrough.
- the motion detection circuit 44 detects the motion of an image according to the output signal of the interpolating circuit 34 and that of the interpolating circuit 36. Then, the signal outputted from the signal switching circuit 43 and subjected to inter-field or inter-frame averaging process and the signal outputted from the interpolating circuit 34 and subjected to the inter-field process only are mixed with each other through the mixing circuit 45 in accordance with the motion of an image thus detected. Accordingly, even in case of moving image, such a signal that no degradation (occurrence of double image or the like) results and aliasing interferences are substantially eliminated can be obtained from the output terminal 46.
- Fig. 6 is a block diagram of a video signal processing apparatus for reducing aliasing interference according to a fourth embodiment of this invention.
- the apparatus of this embodiment has a median-value signal selector 37 for extracting a median-value signal of three adjacent inter-field signals insertedly disposed before the adder 38 of the third embodiment.
- Other components are the same as those of the third embodiment and indicated at the same reference numerals as above.
- the median-value signal selector 37 In order to obtain a signal having eliminated an aliasing interference due to inter-field offset sub-sampling, the median-value signal selector 37 thus disposed extracts a median-value signal of the three adjacent inter-field signals from the output signals of the interpolating circuits 34, 35 and 36.
- the median-value signal thus obtained is subjected to averaging process with an output signal of the interpolating circuit 35 through the adder 38 to obtain a signal having an aliasing interference eliminated.
- the motion detection circuit 44 fails to discriminate the motion of an image, the effect on the moving image in the inter-field averaging process can be reduced.
- the one field difference detection circuit 18 in the first and second embodiments is arranged so as to use all the three adjacent-inter-field signals. However, it may be arranged so as to detect an inter-field difference either before or after the present field.
- the motion detection circuit 22 detects the motion of an image from one inter-frame signal. However, the circuit may detect the motion from two inter-frame signals by taking out further one inter-frame signal additionally.
- the one field difference detection circuit 40 is also arranged so as to use all the three adjacent inter-field signals. However, it may be arranged so as to detect an inter-field difference either before or after the present field.
- the motion detection circuit 44 detects the motion of an image from one inter-frame signal which is subjected to interpolating process. However, it may detect the motion from one inter-frame signal which is before interpolating process to be performed. Yet, it is needless to say that similar to the first and second embodiments, the motion may be detected from two inter-frame signals.
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Description
This invention relates to a video signal processing
apparatus for restoring a high definition television signal
which has been subjected to bandwidth compression using a
sub-Nyquist sub-sampling method and transmitted.
A high definition television (HDTV) signal has a
frequency bandwidth exceeding 20 MHz and is required to be
subjected to bandwidth compression by any means when to be
transmitted using a satellite or the like. As an effective
method for broadly compressing a frequency bandwidth of HDTV
signal, there has been known a sub-Nyquist sub-sampling
method. For which, a multiple sub-Nyquist sampling encoding
(MUSE) system, high definition-multiple analogue component
(HD-MAC) system and the like have been proposed. (See Y.
Ninomiya, et. al., "An HDTV Broadcasting System Utilizing a
Bandwidth Compression Technique - MUSE", IEEE Trans. Vol.BC-33,
No.4, pp.130, 1987, and F.W.P. Vreeswijk, et. al., "HD-MAC
Coding for Compatible Broadcasting of HDTV Signals",
Symposium record Broadcast Session 1989, pp.37 to 53.)
With these methods, as shown in Fig. 11, an offset sub-sampling
is carried out in an inter-field and inter-frame
manner to transmit a quarter of the sample points of an
original signal and as a result, the perfect picture is
transmitted in a four-field mode; so that the bandwidth of
the original signal is compressed quarterly. On the
receiving side, a sample point untransmitted (non-sample
point) is interpolated from the sample point transmitted,
thus restoring the original signal. For example, for the
stationary area, interpolation is made using all sample
points of present field and past three fields. On the other
hand, for the moving area, interpolation is made using only
an intra-field sample point that is transmitted.
As explained above, the stationary area and moving area
are different in interpolating method from each other. As a
result, on the receiving side, the motion of an image is
detected and an image interpolated for the stationary area
and an image interpolated for the moving area are mixed with
each other in accordance with the motion of an image thus
detected, thus restoring the image.
Since such processings as explained above are made on
both transmitting and receiving sides, we can enjoy high
definition television broadcastings at home. However, the
above-mentioned signal processing circuit (decoder) is
extremely expensive and it is estimated to take a
considerably long period of time to make it popular to home-use.
Under such a circumstance, in order to make possible
to display and reproduce-an image with any standard type
television set and video tape recorder (VTR) currently
popular to home-use, there has been known such an apparatus
that high definition television signals of the MUSE system
are converted into current standard type television signals
using a TV signal standard converter, namely, MUSE-NTSC
converter and out of which, a video signal processing
apparatus for performing interpolation in order to restore
an image with a simple structure has been proposed.
As a conventional video signal processing apparatus for
this purpose, see, for example, "MUSE/NTSC Converter for
EDTV", Technical Report of the Institute of Television
Engineers of Japan 1990 BCS90-3 pp.13 to 18.
With a conventional video signal processing apparatus
as shown in Fig. 9, an inputted MUSE signal is sent to an
interpolating circuit to interpolate a non-sample point from
an intra-field sample point in order to restore a bandwidth-compressed
signal. The signal subjected to intra-field
interpolating process, which is equivalent to the moving
image processing of an MUSE decoder, in the interpolating
circuit has signal transmission characteristics as shown in
a frequency characteristics chart of Fig. 12(a). As a
result, for the stationary area, the high resolution
component of a high definition television signal by offset
sub-sampling of the MUSE system as shown in a frequency
characteristics chart of Fig. 12(b) is reproduced as an
aliasing interference, resulting in degradation in image
quality. Then, the signal thus processed through the
interpolating circuit is sent to a frame memory to delay one
frame period and then, the signal thus one-frame delayed and
the signal thus processed interpolation are subjected to
inter-frame averaging process through an adder, thus being
obtainable such a signal that an aliasing interference due
to inter-frame offset sub-sampling is eliminated. In this
case, however, with the moving image, the inter-frame
averaging process makes it possible to occur a double image,
resulting in a degradation in image quality. As a result, a
motion detection circuit detects a motion of an image, and
the signal thus inter-frame averaged and the signal thus
only intra-field interpolated through the interpolating
circuit are mixed with other in a mixing circuit in
accordance with the motion of an image thus detected, so
that even with the moving image, such a signal can be
obtained that has no degradation in image quality as well as
has an aliasing interference due to inter-frame offset sub-sampling
eliminated.
With the structure as above, however, by performing the
inter-frame averaging process, an aliasing interference due
to inter-frame offset sub-sampling can be eliminated thereby
to disappear a flicker component of 15 Hz, but the
bandwidth-compressed MUSE signal contains an aliasing
interference due to inter-field offset sub-sampling still
more. As a result, a high frequency band component
exceeding a horizontal 12 MHz is reproduced as a flicker
component of 30 Hz while being aliased to vertical high
frequency band, so that there arises such a problem that the
interference incompatibly visibly appears in a notched
pattern in the vertical line area of an image so as to be
adhesively formed thereto.
In addition, as another video signal processing
apparatus, it is disclosed in, for example, Japanese Laid-Open
Patent JP-A-4 196 788, published 16/7/92, "Video Signal Standard
Converting Apparatus" (equivalent to EP-A-0 460 928, published 11/12/91).
With a conventional video signal processing apparatus
as shown in Fig. 10, similar to the apparatus shown in Fig.
9, an inputted MUSE signal is subjected to interpolation of
non-sample point from an intra-field sample point in an
interpolating circuit in order to restore a bandwidth-compressed
signal. The signal thus interpolated is sent to
field memories connected in series thereto, then, a median-value
signal of three adjacent inter-field signals is taken
out by a median-value signal selector, an output signal from
the median-value signal selector and output signals from the
field memories are averaged by an adder to obtain an
average-value signal of the signals which are in an inter-field
correlation with each other, thus being possible to
obtain such a signal that the aliasing interference due to
inter-field offset sub-sampling is eliminated. Here, the
averaging process of highly correlated inter-field signals
between three adjacent signals is carried out adaptively, so
that the aliasing interference due to inter-field offset
sub-sampling of the MUSE system can be eliminated without
giving any effect to the moving image.
With the structure as above, however, by performing an
optimum inter-field averaging process between three adjacent
fields, the aliasing interference due to inter-field offset
sub-sampling can be eliminated and as a result, the flicker
component of 30 Hz which is visibly appeared in a notched
pattern in the vertical line area of an image so as to be
adhesively formed thereto can be disappeared, however, the
bandwidth-compressed MUSE signal contains the aliasing
interference due to inter-frame offset sub-sampling still
more, thus arising such a problem that a flicker component
of 15 Hz is remained in the oblique component of the image.
US-A-4 768 092 discloses the use of interpolation and
averaging to convert a video signal to a higher resolution.
Field and line differences are used to select various averaged signals.
An object of this invention is to provide a video
signal processing apparatus capable of eliminating both an
aliasing interference due to inter-frame offset sub-sampling
and aliasing interference due to inter-field offset sub-sampling.
In order to attain the above-mentioned object, a video
signal processing apparatus of this invention comprises an
interpolating circuit for interpolating a non-sample point
from intra-field sample points in order to restore a high
definition television signal which has been bandwidth-compressed
by offset sub-sampling, a first memory for
delaying a signal thus interpolated for one field period, a
second memory for delaying an output signal of the first
memory for further one field period, a first adder for
performing an adjacent inter-field averaging process from
input and output signals of the first and second memories, a
second adder for performing an inter-frame averaging process
from an input signal of the first memory and an output
signal of the second memory, a correlation discriminating
circuit for detecting one field difference and one frame
difference from input and output signals of the first and
second memories and for outputting a switching signal in
accordance with magnitudes of the differences thus detected,
and a signal switching circuit for switching an output
signal of the first adder and an output signal of the second
adder in accordance with the output switching signal from
the correlation discriminating circuit. Preferably, this
apparatus may further comprise a motion detection circuit
for detecting a motion of an image from an input signal of
the first memory and an output signal of the second memory,
and a mixing circuit for mixing an output signal of the
signal switching circuit and an input/output signal of the
first memory in accordance with the motion of an image thus
detected.
Another video signal processing apparatus of this
invention comprises a first memory for delaying the
bandwidth-compressed high definition television signal for
one field period, a second memory for delaying an output
signal of the first memory for further one field period,
first, second and third interpolating circuits for
interpolating non-sample points from intra-field sample
points in order to restore a sub-sampled signal in
accordance with input and output signals of the first and
second memories, a first adder for performing an adjacent
inter-field averaging process from output signals of the
first, second and third interpolating circuits, a second
adder for performing an inter-frame averaging process from
an output signal of the first interpolating circuit and an
output signal of the third interpolating circuit, a
correlation discriminating circuit for detecting one field
difference and one frame difference from output signals of
the first, second and third interpolating circuits and for
outputting a switching signal in accordance with magnitudes
of the differences thus detected, and a signal switching
circuit for switching an output signal of the first adder
and an output signal of the second adder in accordance with
the switching signal from the correlation discriminating
circuit. This apparatus may further comprise a motion
detection circuit for detecting a motion of an image from an
output signal of the first interpolating circuit and an
output signal of the third interpolating circuit or from an
input signal of the first memory and an output signal of the
second memory, and a mixing circuit for mixing an output
signal of the signal switching circuit and an output signal
of the first or second interpolating circuit in accordance
with the motion of an image thus detected.
As arranged as above, a television signal subjected to
intra-field interpolation is supplied to two memories.
Then, an inter-field averaging process is performed between
the present field and correlative adjacent field before or
after for eliminating an aliasing interference due to inter-field
offset sub-sampling, and an inter-frame averaging
process is performed for eliminating an aliasing
interference due to inter-frame offset sub-sampling. Larger
one of these aliasing interferences is discriminated in
accordance with the magnitudes of an inter-field difference
and an inter-frame difference to be switched. Accordingly,
not only the aliasing interference due to inter-field offset
sub-sampling but also the aliasing interference due to
inter-frame offset sub-sampling can be eliminated. In
addition, the motion of an image Is detected, and the signal
subjected to the inter-field averaging process between the
present field and correlative adjacent field before or
after, the signal subjected to the inter-frame averaging
process, and the signal subjected to the intra-field
interpolation are mixed with each other. Accordingly, even
in case of a moving image, degradations including occurrence
of double image can be prevented from being taken place.
Furthermore, as arranged as above, such aliasing
interferences that are caused by inter-field and inter-frame
offset sub-samplings can be eliminated. At the same time, a
memory for storing signals before interpolation is provided
thereby to make a reduction in memory capacity possible.
Fig. 1 is a block diagram of a video signal processing
apparatus for reducing an aliasing interference according to
a first embodiment of this invention.
Fig. 2 is a block diagram showing in detail a circuit
for detecting inter-field and inter-frame aliasing
interferences to be taken place in the apparatus shown in
Fig. 1.
Fig. 3 is a characteristics chart for explaining the
operation of detecting aliasing interferences in the
apparatus shown in Fig. 1.
Fig. 4 is a block diagram of a video signal processing
apparatus for reducing an aliasing interference according to
a second embodiment of this invention.
Fig. 5 is a block diagram of a video signal processing
apparatus for reducing an aliasing interference according to
a third embodiment of this invention.
Fig. 6 is a block diagram of a video signal processing
apparatus for reducing an aliasing interference according to
a fourth embodiment of this invention.
Fig. 7 is a block diagram of a median-value selection
circuit in the apparatus shown in Figs. 2 and 4.
Fig. 8 is a waveform diagram for explaining the
operation of eliminating an inter-field aliasing
interference in the apparatus shown in Figs. 2 and 4.
Fig. 9 is a block diagram of a video signal processing
apparatus for reducing an aliasing interference of the prior
art.
Fig. 10 is a block diagram of another video signal
processing apparatus for reducing an aliasing interference
of the prior art.
Fig. 11 is a diagram for explaining the principle of a
bandwidth compression method by MUSE system offset sub-sampling.
Fig. 12 is a frequency characteristics chart for
explaining occurrence of an aliasing interference due to
MUSE system offset sub-sampling in intra-field
interpolation.
Fig. 1 is a block diagram of a video signal processing
apparatus for reducing aliasing interference according to a
first embodiment of this invention, which comprises an input
terminal 11 for receiving a high definition television
signal which has been bandwidth-compressed by offset sub-sampling
(hereinafter typically expressed as an MUSE
signal), an interpolating circuit 12 for interpolating a
non-sample point from an inter-field sample point in order
to restore a bandwidth-compressed signal, field memories 13
and 14, adders 16 and 17 each for performing averaging
process, a one field difference detection circuit 18 for
detecting an aliasing interference due to inter-field offset
sub-sampling, a one frame difference detection circuit 19
for detecting an aliasing interference due to inter-frame
offset sub-sampling, a correlation discriminating circuit 20
for discriminating larger one of the inter-field and inter-frame
aliasing interferences, and a signal switching circuit
21, and further comprising a motion detection circuit 22, a
mixing circuit 23, and an output terminal 24 for taking out
a high definition television signal having aliasing
interferences eliminated therefrom.
With the apparatus structured as above, the operation
will be explained below.
The MUSE signal inputted from the input terminal 11 is
sent to the interpolating circuit 12 to interpolate a non-sample
point from inter-field sample points in order to
restore a bandwidth-compressed signal. Next, the signal
thus interpolated is sent to the field memories 13 and 14
connected in series. An output signal of the interpolating
circuit 12 and an output signal of the field memory 13 is
subjected to inter-field averaging process through the adder
16 to obtain a signal having an aliasing interference due to
inter-field offset sub-sampling eliminated. On the other
hand, the output signal of the interpolating circuit 12 and
an output signal of the memory 14 are subjected to inter-frame
averaging process through the adder 17 to obtain a
signal having an aliasing interference due to inter-frame
offset sub-sampling eliminated. In addition, input and
output signals of the field memories 13 and 14 are
respectively sent to the one field difference detection
circuit 18 and one frame difference detection circuit 19 to
detect an aliasing interference due to inter-field offset
sub-sampling and an aliasing interference due to inter-frame
offset sub-sampling, and sent to the correlation
discriminating circuit 20 to discriminate larger one of the
inter-field and inter-frame aliasing interferences. Thus,
the signal switching circuit 21 controls the signal having
an aliasing interference due to inter-field offset sub-sampling
eliminated outputted from the adder 16 and the
signal having an aliasing interference due to inter-frame
offset sub-sampling eliminated outputted from the adder 17
so as to transmit the signal having eliminated the larger
one of the inter-field and inter-frame aliasing
interferences.
In addition, the motion detection circuit 22 detects
the motion of an image from the input signal of the field
memory 13 and the output signal of the field memory 14. The
signal outputted from the signal switching circuit 21, which
is obtained by switching through the circuit 21 the signal
subjected to inter-field averaging process before or after
and the signal subjected to inter-frame averaging process,
and the signal subjected to intra-field processing only
outputted from the interpolating circuit 12 are mixed with
each other through the mixing circuit 23 in accordance with
the motion of an image thus detected. Accordingly, even in
case of moving image, no degradation (occurrence of a double
image) results, so that such a signal that aliasing
interferences are substantially eliminated can be obtained
from the output terminal 24.
As explained above, according to this embodiment,
intra-field interpolation equivalent to the moving image
process of an MUSE decoder is carried out in the
interpolating circuit 12. Then, for the aliasing
interference to be induced in case of stationary image, the
inter-field averaging process of the output signal of the
interpolating circuit 12 and the output of the field memory
13 is carried out through the adder 16 to obtain such a
signal that the aliasing interference due to inter-field
offset sub-sampling is eliminated. At the same time, the
inter-frame averaging process of the output signal of the
interpolating circuit 12 and the output signal of the field
memory 14 is carried out through the adder 17 to obtain such
a signal that the aliasing interference due to inter-frame
offset sub-sampling is eliminated. Then, with these two
signals thus obtained, in order to detect the state of
inter-field and inter-frame aliasing interferences from the
signals of three adjacent fields, the one field difference
detection circuit 18 for detecting the absolute value of an
inter-field difference from these signals of the three
adjacent fields, the one frame difference detection circuit
19 for detecting the absolute value of an inter-frame
difference therefrom and the correlation discriminating
circuit 20 for comparing these differences to detect larger
one of them in magnitude are disposed as shown in Fig. 2.
As shown in Fig. 3, in accordance with the value of the
inter-field aliasing interference becoming a flicker
component of 30 Hz and the value of the inter-frame aliasing
interference becoming a flicker component of 15 Hz, the
signal subjected to processing for which is larger in
aliasing interference is switched by the switching circuit
21 to be outputted.
Accordingly, such a signal that aliasing interferences
due to inter-field and inter-frame offset sub-samplings are
eliminated can be obtained from the switching circuit 21.
Fig. 4 is a block diagram of a video signal processing
apparatus for reducing aliasing interference according to a
second embodiment of this invention. In which, a median-value
signal selector 15 for extracting a median-value
signal of three adjacent inter-field signals is additionally
provided to the apparatus of the first embodiment so as to
be disposed before the adder 16, and other components are
the same as those in the first embodiment and indicated at
the same referential numerals as above.
In order to obtain such a signal that the aliasing
interference due to inter-field offset sub-sampling, the
median-value signal selector 15 extracts a median-value
signal of three adjacent inter-field signals from
input/output signals of the field memories 13 and 14. Then,
the median-value signal thus obtained and the output signal
of the memory 13 are subjected to averaging process through
the adder 16 to obtain a signal having aliasing interference
eliminated.
In addition, the median-value signal selector 15
compares, as shown in Fig. 7, the magnitudes of respective
two signals of three signals inputted with each other to
detect a median-value signal on an amplitude selection basis
therefrom. The selection means is switched in accordance
with the result thus detected to output the median-value
signal.
In addition, the median-value signal selector 15 is not
limited to that shown in Fig. 7, but any circuit can be used
for this purpose if it can extract a median-value signal.
Theoretical values of median-value selection in the median-value
signal selector 15 are tabulatedly shown below.
| Magnitude relations of signals (ascending order) | Outputs of comparator | Selected signals | ||||
| A | B | C | A>B | A>C | B>C | MID |
| 2 | 1 | 3 | 0 | 1 | 1 | A |
| 2 | 3 | 1 | 1 | 0 | 0 | A |
| 1 | 2 | 3 | 1 | 1 | 1 | |
| 3 | 2 | 1 | 0 | 0 | 0 | |
| 1 | 3 | 2 | 1 | 1 | 0 | |
| 3 | 1 | 2 | 0 | 0 | 1 | |
| 1 | 1 | 2 | 1 | 1 | 1 | |
| 2 | 2 | 1 | 1 | 0 | 0 | A |
| 1 | 2 | 1 | 1 | 1 | 0 | |
| 2 | 1 | 2 | 0 | 1 | 1 | A |
| 2 | 1 | 1 | 0 | 0 | 1 | |
| 1 | 2 | 2 | 1 | 1 | 1 | |
| 1 | 1 | 1 | 1 | 1 | 1 | B |
Next, the operation for eliminating an aliasing
interference will be explained in detail while referring to
Fig. 8 which is a waveform diagram for explaining the
operation of eliminating an aliasing interference as an
example.
In a stationary area or at a changing point of motion,
a median-value signal X (shown at marks in Fig. 8) taken
out through the median-value signal selector 15 becomes a
signal before or after a signal Y of the present field
(shown at o ○ marks in Fig. 8) as shown in Figs. 8(a) and (b).
Accordingly, by being subjected to the inter-field averaging
process on the median-value signal X and the signal Y of the
present field through the adder 16, the aliasing component
due to inter-field offset sub-sampling can be eliminated.
On the other hand, in a moving area where an inputted
television signal has a motion, as shown in Fig. 8(c), the
median-value signal X taken out through the median-value
signal selector 15 becomes the signal Y of the present
field. This means that the signal Y of the present signal
itself can be obtained, resulting in obtaining no
degradation in image quality. Accordingly, the averaging
process is performed adaptively on inter-field signals high
in correlation between adjacent three fields, so that the
aliasing interference due to inter-field offset sub-sampling
of the MUSE system can be eliminated without giving any
effect to the moving image itself. Further, even if the
motion detection circuit 22 fails to discriminate the motion
of an image, the effect of the inter-field averaging process
on the moving image can be made small.
Fig. 5 is a block diagram of a video signal processing
apparatus for reducing an aliasing interference according to
a third embodiment of this invention, which comprises an
input terminal 31 for receiving an MUSE signal, field
memories 32 and 33, intra-field interpolating circuits 34,
35 and 36 each for interpolating a non-sample point from
intra-field sample points in order to restore a bandwidth-compressed
MUSE signal, adders 38 and 39 for performing
averaging processes, a one field difference detection
circuit 40 for detecting an aliasing interference due to
inter-field offset sub-sampling, a one frame difference
detection circuit 41 for detecting an aliasing interference
due to inter-frame offset sub-sampling, a correlation
discriminating circuit 42 for discriminating larger one of
the inter-field and inter-frame aliasing interferences, and
a signal switching circuit 43, further comprising a motion
detection circuit 44, a mixing circuit 45 and an output
terminal 46 for taking out a high definition television
signal having aliasing interferences eliminated.
The operation of this apparatus will be explained
below. MUSE signal inputted from the input terminal 31 is
stored in the field memories 32 and 33 connected in series.
Then, subjected to interpolation of a non-sample point from
an intra-field sample point for a bandwidth-compressed
signal of each of three adjacent fields. Next, an output
signal of the interpolating circuit 34 and an output signal
of the interpolating circuit 35 are subjected to inter-field
averaging process through the adder 38 to obtain a signal
having an aliasing interference due to inter-field offset
sub-sampling eliminated. On the other hand, an output
signal of the interpolating circuit 34 and an output signal
of the interpolating circuit 36 are subjected to inter-frame
averaging process through the adder 39 to obtain a signal
having an aliasing interference due to inter-frame offset
sub-sampling eliminated. In addition, interpolated signals
of three adjacent fields of the interpolating circuits 34,
35 and 36 are sent to the one field difference detection
circuit 40 and one frame difference detection circuit 41 to
respectively detect the aliasing interference due to inter-field
offset sub-sampling and the aliasing interference due
to inter-frame offset sub-sampling. And then, the inter-field
and inter-frame aliasing interferences are
discriminated larger one of them through the correlation
discriminating circuit. Then, the switching circuit 43
controls the signal outputted from the adder 38 and having
eliminated the aliasing interference due to inter-field sub-sampling
by performing inter-field averaging process between
the present field and correlative adjacent one before or
after and the signal outputted from the adder 39 and having
eliminated the aliasing interference due to inter-frame
offset sub-sampling, so that the signal having eliminated
larger one of these inter-field and inter-frame aliasing
interferences can be passed therethrough.
In addition, the motion detection circuit 44 detects
the motion of an image according to the output signal of the
interpolating circuit 34 and that of the interpolating
circuit 36. Then, the signal outputted from the signal
switching circuit 43 and subjected to inter-field or inter-frame
averaging process and the signal outputted from the
interpolating circuit 34 and subjected to the inter-field
process only are mixed with each other through the mixing
circuit 45 in accordance with the motion of an image thus
detected. Accordingly, even in case of moving image, such a
signal that no degradation (occurrence of double image or
the like) results and aliasing interferences are
substantially eliminated can be obtained from the output
terminal 46.
As explained above, according to this embodiment, by
disposing field memories for obtaining three adjacent inter-field
signals so as to store a television signal before
interpolation, aliasing interferences due to inter-field and
inter-frame offset sub-samplings of the MUSE system can be
almost perfectly eliminated and a field memory to be used
can be reduced to half in capacity.
Fig. 6 is a block diagram of a video signal processing
apparatus for reducing aliasing interference according to a
fourth embodiment of this invention. The apparatus of this
embodiment has a median-value signal selector 37 for
extracting a median-value signal of three adjacent inter-field
signals insertedly disposed before the adder 38 of the
third embodiment. Other components are the same as those of
the third embodiment and indicated at the same reference
numerals as above.
In order to obtain a signal having eliminated an
aliasing interference due to inter-field offset sub-sampling,
the median-value signal selector 37 thus disposed
extracts a median-value signal of the three adjacent inter-field
signals from the output signals of the interpolating
circuits 34, 35 and 36. The median-value signal thus
obtained is subjected to averaging process with an output
signal of the interpolating circuit 35 through the adder 38
to obtain a signal having an aliasing interference
eliminated. As a result, similar to the second embodiment,
even when the motion detection circuit 44 fails to
discriminate the motion of an image, the effect on the
moving image in the inter-field averaging process can be
reduced.
In addition, the one field difference detection circuit
18 in the first and second embodiments is arranged so as to
use all the three adjacent-inter-field signals. However, it
may be arranged so as to detect an inter-field difference
either before or after the present field. Also, the motion
detection circuit 22 detects the motion of an image from one
inter-frame signal. However, the circuit may detect the
motion from two inter-frame signals by taking out further
one inter-frame signal additionally. In the third and
fourth embodiment, the one field difference detection
circuit 40 is also arranged so as to use all the three
adjacent inter-field signals. However, it may be arranged
so as to detect an inter-field difference either before or
after the present field. The motion detection circuit 44
detects the motion of an image from one inter-frame signal
which is subjected to interpolating process. However, it
may detect the motion from one inter-frame signal which is
before interpolating process to be performed. Yet, it is
needless to say that similar to the first and second
embodiments, the motion may be detected from two inter-frame
signals.
Claims (12)
- A video signal processing apparatus for reducing aliasing interference comprising:interpolating means (12) which receives a high definition television signal which has been bandwidth-compressed by offset sub-sampling for interpolating a non-sample point from intra-field sample points of a sub-sampled signal;field averaging means (16) for performing an inter-field averaging process from data of three adjacent fields of a signal thus interpolated;frame averaging means (17) for performing an inter-frame averaging process; anddifference detection means (18,19) for detecting one field difference and one frame difference and signal switching means (21) for switching an output signal of said inter-field averaging means and an output signal of said inter-frame averaging means in accordance with magnitudes of the differences thus detected.
- A video signal processing apparatus according to claim 1, further comprising:a motion detection circuit (22) for detecting a motion of an image from data of two fields out of three adjacent fields of an interpolated signal; anda mixing circuit (23) for mixing an output signal of said signal switching means and an output signal of said interpolating means in accordance with the motion of an image thus detected.
- A video signal processing apparatus for reducing aliasing interference comprising:interpolating means (12) which receives a high definition television signal which has been bandwidth-compressed by offset sub-sampling for interpolating a non-sample point from intra-field sample points to a sub-sampled signal;first memory means (13) for delaying a signal thus interpolated for one field period;second memory means (14) for delaying an output signal of said first memory means for further one field period;first adder means (16) for performing an inter-field averaging process from an input signal of said first memory means and an output signal of said first memory means;second adder means (17) for performing an inter-frame averaging process from an input signal of said first memory means and an output signal of said second memory means;correlation discriminating means (18,19,20) for detecting one field difference and one frame difference from input and output signals of said first and second memory means and for outputting a switching signal in accordance with magnitudes of the differences thus detected; andsignal switching means (21) for switching an output signal of said first adder means and an output signal of said second adder means in accordance with the switching signal from said correlation discriminating means.
- A video signal processing apparatus according to claim 3, further comprising:a motion detection circuit (22) for detecting a motion of an image from an input signal of said first memory and an output signal of said second memory; anda mixing circuit (23) for mixing an output signal of said switching means and an input signal of said first memory means in accordance with the motion of an image thus detected.
- A video signal processing apparatus for reducing aliasing interference comprising:first memory means (32) for delaying a high definition television signal which has been bandwidth-compressed by offset sub-sampling for one field period;second memory means (33) for delaying an output signal of said first memory means for further one field period;first, second and third interpolating means (34-36) for respectively interpolating non-sampling points from intra-field sample points of a sub-sampled signal in accordance with input and output signals of said first and second memory means;first adder means (38) for performing an inter-field averaging process from an output signal of said first interpolating means and an output signal of said second interpolating means;second adder means (39) for performing an inter-frame averaging process from an output signal of said first interpolating means and an output signal of said third interpolating means;correlation discriminating means (40-42) for detecting one field difference and one frame difference from output signals of said first, second and third interpolating means and for outputting a switching signal in accordance with magnitudes of differences thus detected; andsignal switching means (43) for switching an output signal of said first adder means and an output signal of said second adder means in accordance with the switching signal from said correlation discriminating means.
- A video signal processing apparatus according to claim 5, further comprising:a motion detection circuit (44) for detecting a motion of an image from an output signal of said first interpolating means and an output signal of said third interpolating means; anda mixing circuit (45) for mixing an output signal of said signal switching means and an output signal of said first interpolating means in accordance with the motion of an image thus detected.
- A video signal processing apparatus according to claim 5, further comprising:a motion detection circuit (44,22) for detecting a motion of an image from an input signal of said first memory means and an output signal of said second memory means; anda mixing circuit (45,23) for mixing an output signal of said signal switching means and an output signal of said first interpolating means in accordance with the motion of an image thus detected.
- A video signal processing apparatus for reducing aliasing interference comprising:interpolating means (12) which receives a high definition television signal which has been bandwidth-compressed by offset sub-sampling for interpolating a non-sample point from intra-field sample points of a sub-sampled signal;first memory means (13) for delaying a signal thus interpolated for one field period;second memory means (14) for delaying an output signal of said first memory means for further one field period;median-value signal selection means (15) for extracting a median-value signal of three adjacent inter-field signals from input and output signals of said first and second adder means;first adder means (16) for averaging an output signal of said first memory means (13) and an output signal of said medianvalue signal selection means (15);second adder means (17) for performing an inter-frame averaging process from an input signal of said first memory means and an output signal of said second memory means;correlation discriminating means (18-20) for detecting one field difference and one frame difference from input and output signals of said first and second memory means and for outputting a switching signal in accordance with magnitudes of differences thus detected; andsignal switching means (21) for switching an output signal of said first adder means an output signal of said second adder means in accordance with the switching signal from said correlation discriminating means.
- A video signal processing apparatus according to ciaim 8, further comprising:a motion detection circuit (22) detecting a motion of an image from an input signal of said first memory means and an output signal of said second memory means; andmixing means (23) for mixing an output signal of said signal switching means and an output signal of said first memory means in accordance with the motion of an image thus detected.
- A video signal processing apparatus for reducing aliasing interference comprising:first memory means (32) for delaying a high definition television signal which has been bandwidth-compressed by offset sub-sampling for one field period;second memory means (33) for delaying an output signal of said first memory means for further one field period;first, second and third interpolating means (34-36) for respectively interpolating non-sample points from intra-field sample points of a sub-sampled signal in accordance with input and output signals of said first and second memory means;median-value signal selection means (37) for extracting a median-value signal of three adjacent inter-field signals from output signals of said first, second and third interpolating means (34-36);first adder means (38) for averaging an output signal of said second interpolating means and an output signal of said median-value signal selection means;second adder means (39) for performing an inter-frame averaging process from an output signal of said first interpolating means and an output signal of said third interpolating means;correlation discriminating means (40-42) for detecting one field difference and one frame difference from output signals of said first, second and third interpolating circuits and for outputting a switching signal in accordance with the magnitudes of differences thus detected; andsignal switching means (43) for switching an output signal of said adder means and an output signal of said second adder means in accordance with the switching signal from said correlation discriminating means.
- A video signal processing apparatus according to claim 10, further comprising:a motion detection circuit (44) for detecting a motion of an image from an output signal of said first interpolating means and an output signal of said third interpolating means; anda mixing circuit (45) for mixing an output signal of said signal switching means and an output signal of said second interpolating means in accordance with the motion of an image thus detected.
- A video signal processing apparatus according to claim 10, further comprising:a motion detection circuit (44,22) for detecting a motion of an image from an input signal of said first memory means and an output signal of said second memory means; anda mixing circuit (45,23) for mixing an output signal of said signal switching means and an output signal of said second interpolating means.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP179474/91 | 1991-07-19 | ||
| JP3179474A JPH0817480B2 (en) | 1991-07-19 | 1991-07-19 | Video signal processing device |
| JP3186115A JPH0815336B2 (en) | 1991-07-25 | 1991-07-25 | Video signal processing device |
| JP186115/91 | 1991-07-25 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0524009A2 EP0524009A2 (en) | 1993-01-20 |
| EP0524009A3 EP0524009A3 (en) | 1994-08-24 |
| EP0524009B1 true EP0524009B1 (en) | 1998-09-16 |
Family
ID=26499321
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP92306558A Expired - Lifetime EP0524009B1 (en) | 1991-07-19 | 1992-07-17 | Video signal processing apparatus for reducing aliasing interference |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5327241A (en) |
| EP (1) | EP0524009B1 (en) |
| DE (1) | DE69226994T2 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993000771A1 (en) * | 1991-06-27 | 1993-01-07 | Nippon Hoso Kyokai | Sub-sampling transmission system for improving transmitted picture quality in time-varying picture region of wide-band color picture signal |
| US5446501A (en) * | 1992-10-22 | 1995-08-29 | Accom, Incorporated | Three-dimensional median and recursive filtering apparatus and method for video image enhancement |
| KR0140674B1 (en) * | 1993-04-12 | 1998-06-15 | 모리시다 요이치 | Method for image signal processing |
| JP3527259B2 (en) * | 1993-04-12 | 2004-05-17 | 松下電器産業株式会社 | Video signal processing apparatus and processing method |
| US6137835A (en) * | 1993-11-16 | 2000-10-24 | Canon Kabushiki Kaisha | Picture coding apparatus using orthogonal transforms |
| US5574512A (en) * | 1994-08-15 | 1996-11-12 | Thomson Consumer Electronics, Inc. | Motion adaptive video noise reduction system |
| DE102004032783A1 (en) * | 2004-07-06 | 2006-02-16 | Conradi + Kaiser Gmbh | Plate for the formation of a covering, in particular for outdoor use, and covering |
| JP4207009B2 (en) * | 2005-03-09 | 2009-01-14 | ソニー株式会社 | Image processing apparatus and method |
| EP1837826A1 (en) * | 2006-03-20 | 2007-09-26 | Matsushita Electric Industrial Co., Ltd. | Image acquisition considering super-resolution post-interpolation |
| JP4973031B2 (en) * | 2006-07-03 | 2012-07-11 | ソニー株式会社 | Noise suppression method, noise suppression method program, recording medium recording noise suppression method program, and noise suppression device |
| US9300906B2 (en) * | 2013-03-29 | 2016-03-29 | Google Inc. | Pull frame interpolation |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4551753A (en) * | 1981-12-17 | 1985-11-05 | Nippon Hoso Kyokai | Picture signal processing system including spatio-temporal filter |
| CA1213359A (en) * | 1983-10-19 | 1986-10-28 | Yoshinori Izumi | Multiplex subsampling transmission system for a high definition color television picture signal |
| US4768092A (en) * | 1986-07-23 | 1988-08-30 | Canon Kabushiki Kaisha | Image signal conversion device |
| JPH01320887A (en) * | 1988-06-22 | 1989-12-26 | Sharp Corp | Reproducing system for transmission television signal |
| JPH0279574A (en) * | 1988-09-16 | 1990-03-20 | Atein Kaihatsu Kk | Video signal transmission system |
| JP2576612B2 (en) * | 1988-12-28 | 1997-01-29 | 日本ビクター株式会社 | Signal converter |
| JPH0683435B2 (en) * | 1989-02-03 | 1994-10-19 | 三洋電機株式会社 | Subsample video signal demodulator |
| US4967271A (en) * | 1989-04-05 | 1990-10-30 | Ives C. Faroudja | Television scan line doubler including temporal median filter |
| US4989090A (en) * | 1989-04-05 | 1991-01-29 | Yves C. Faroudja | Television scan line doubler including temporal median filter |
| JPH03242098A (en) * | 1990-02-20 | 1991-10-29 | Sony Corp | Video signal transmission system |
| EP0460928A3 (en) * | 1990-06-07 | 1993-09-01 | Matsushita Electric Industrial Co., Ltd. | Video signal converting apparatus |
-
1992
- 1992-07-17 DE DE69226994T patent/DE69226994T2/en not_active Expired - Fee Related
- 1992-07-17 EP EP92306558A patent/EP0524009B1/en not_active Expired - Lifetime
- 1992-07-20 US US07/915,551 patent/US5327241A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0524009A2 (en) | 1993-01-20 |
| US5327241A (en) | 1994-07-05 |
| EP0524009A3 (en) | 1994-08-24 |
| DE69226994D1 (en) | 1998-10-22 |
| DE69226994T2 (en) | 1999-02-18 |
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